The present invention relates to solar-collecting apparatus, and more particularly, to apparatus adapted to cover a portion of a structure to provide heat thereto.
Solar collecting units designed to provide space heating in a dwelling are known in the prior art. Typically, these are elongate units adapted to be joined edge-to-edge to cover that portion of a dwelling which is exposed to the sun. One such prior art unit includes an elongate housing having therein a pair of parallel spaced apart plates, the outer one of which is constructed to collect solar energy, and the inner one of which forms with the solar-collecting panel, an elongate plenum which communicates with an inlet and outlet located adjacent opposite ends the housing. Forced air circulating through the plenum from its inlet toward its outlet end is warmed by passage through the plenum alongside the solar-collecting panel.
For a variety of reasons, a solar-collecting unit of the type just described may not operate at optimal efficiency. Air flowing between the two panels becomes progressively hotter as it approaches the unit's outlet end. This produces, in effect, heat transfer from the outer, solar-collecting panel to the inner panel, from which heat may be transferred to the unit's housing, and from there to the atmosphere. Air flow through the unit between the two panels is substantially unobstructed, and therefore characteristically laminar. As a result heat transfer from the solar-heated panel to the air flowing through the unit may be incomplete. In many prior art solar-collector units, the solar-collecting panel is attached directly to the unit's metal housing. This construction facilitates heat transfer from the outer and inner panels to the housing, this being lost heat.
In the installation of solar-collector units known in the prior art, it is necessary to precut, in each area on the structure which is to receive a unit, a pair of spaced apart openings for accessing the inlet and outlet in each unit.
One object of the present invention is to provide a solar-collecting apparatus which substantially overcomes the above-mentioned problems associated with solar-collecting units in the prior art.
A more specific object of the invention is to provide such apparatus constructed to produce efficient transfer of solar-collected heat to air circulating through the unit.
It is another object of the invention to provide solar-collecting apparatus having a pair of elongate plenums through which air circulates, in reverse directions, from an inlet to an outlet located adjacent a common end of the apparatus.
Yet another object of the invention is to provide such apparatus constructed to create intimate contact between a solar-heated panel and air circulating through the apparatus.
Another object of the invention is to provide, in such apparatus, a solar-collector panel which is insulated from the apparatus' housing.
The present invention in solar-collecting apparatus includes an elongate housing and a solar-collecting panel mounted therein for collecting solar energy in the form of heat. A second panel in the housing forms with a housing backing and the solar-collecting panel, inner and outer plenums, respectively, which communicate with each other adjacent one end of the housing. Inlet and outlet ports adjacent the other end of the housing communicate with the inner and outer plenums, respectively, creating an air passageway from the inlet through the inner plenum, in one direction, and in the opposite direction, through the outer plenum toward the outlet. Baffle structure placed between the two panels acts to increase the path of travel of air flowing through the outer panel alongside the solar-collecting panel.
In a preferred embodiment of the invention, the backing covers one side of the housing, with the opposite side of the housing being covered by a glazing. The solar-collecting panel is insulated from the housing and spaced from the glazing, forming therebetween a closed, insulative air space. The baffle structure comprises a plurality of heat-conductive mesh elements which interconnect the two panels and are distributed laterally and longitudinally therealong.